Pipe fitting

ABSTRACT

A pipe fitting adapted to connect a section of plastic pipe to a fitting body. The fitting comprises a hollow metallic body into which is disposed a plastic sleeve. An annular ring is disposed within the sleeve. A second sleeve is disposed within the hollow body and is attached to the ring such that a socket is defined by the first and second sleeves. The socket has a transverse dimension slightly in excess of the wall thickness of the plastic pipe so that the pipe may be snugly received within the socket. A gasket and compression nut provide sealing between the plastic pipe and the fitting body.

United States Patent 1 'Alewitz PIPE FITTING [75] Inventor: Sam Alewitz,Painesville, Ohio [73] Assignee: Perfection Corporation, Madison,

Ohio

[22] Filed: Apr. 29, 1971 [21] Appl. No.: 138,608

FOREIGN PATENTS OR APPLICATIONS 854,939 1/1940 France .L ..285/371 [451Apr. 10, 1973 Primary Examiner-Dave W. Arola Attorney-Fay, Sharpe andMulholland ABSTRACT A pipe fitting adapted to connect a section ofplastic pipe to a fitting body. The fitting comprises a hollow metallicbody into which is disposed a plastic sleeve. An annular ring isdisposed within the sleeve. A second sleeve is disposed within thehollow body and is attached to the ring such that a socket is defined bythe first and second sleeves. The socket has a trans verse dimensionslightly in excess of the wall thickness of the plastic pipe so that thepipe may be snugly received within the socket. A gasket and compressionnut provide sealing between the plastic pipe and the fitting body.

7 Claim, 2 Drawing Figures PIPE FITTING BACKGROUND OF THE INVENTION Thisinvention relates to a pipe fitting for interconnecting lengths ofplastic pipe or, alternately, for interconnecting a length of plasticpipe with a length of metal pipe.

The underground transmission of natural gas and other such fluids isusually accomplished by means of heavy black steel pipe. More recently,however, the use of plastic pipe in gas applications has become moreevident. Similarly, plastic pipe has been increasingly used in the aboveground transmission of corrosive fluids. Thus, there has developed aneed for a fitting by means of which a length of plastic pipe can beconnected to a length of steel pipe or, alternately, in which a lengthof plastic pipe can be connected to another length of plastic pipe.

This invention is directed to a transition pipe fitting by means ofwhich plastic pipe may be connected to steel or other metal pipe. v

This invention is further directed to a coupling means for securingplastic or other pipe to a fitting body so that the pipe may beinterconnected in fluid communication with another pipe of eitherplastic or metallic construction. This invention, thus, is broadlyapplicable to plastic-to-plastic or plastic-to-metal pipe fittings.

BRIEF DESCRIPTION OF THE INVENTION Briefly described, this inventionprovides a pipe fitting comprising a generally cylindrical hollow bodyand including first and second attaching means to secure first andsecond pipes to said body in fluid communication. When it is desired toconnect a metal pipe to the fitting, the first attaching means may takethe form of internal threads in the fitting body.

The second attaching means of the fitting body serves the purpose ofrigidly securing plastic pipe to the body. Such second attaching meansis comprised of a first sleeve received within a body and an annularring extending generally radially inwardly from the sleeve. A secondsleeve is secured. to the ring and is spaced from the first sleeve thusdefining a socket into which a second pipe may be disposed. Thedimensional characteristics of the socket are such that the second pipeis snugly received within the socket. Adhesive or other suitable joiningmaterials may be used to enhance the retention of the second pipe in thesocket. Gripping and sealing means in the form of an elastomeric gasketand a compression nut threadedly engaged with thefitting body areprovided for the purpose of sealing the fitting body and the pipe.

DESCRIPTION OF THE INVENTION A more complete description of theinvention will now be made with reference to the attached drawings inwhich:

FIG. 1 is an elevational cross-sectional view of a female connector ofthis invention in which a plastic pipe is joined in fluid communicationwith a metal pipe; and

FIG. 2 is an elevational cross-sectional view of a union fitting of thisinvention in which two plastic pipes are joined in fluid communicationend-to-end.

Turning now to FIG. I, there is shown a fitting I0 in the form of afemale connector element. Fitting 10 is comprised of a generallycylindrical hollow body 12 having first and second attaching means l4,16 for the purpose of securing first and second pipes 18, 20 to body 12.In the embodiment of FIG. 1, pipe 18 is a black steel pipe such as usedin gas service and includes external pipe threads 22 at one end thereof.Threads 22 are adapted to engage complementary threads 24 defined on aninternal surface of body 12. Such internal surface is defined as byforming a land 26 in body 12 by means of a roll die or the like.

In a roll die operation a portion of body 12 is upset thus to define aland 26 having a prescribed length. The length of land 26 may be varieddepending upon particular conditions and the desired number of threadsrequired on the fitting body in order to receive pipe 18. For a morecomplete description of a roll die operation reference is made to theJacobson US. Pat. No. 3,093,161.

The second attaching means 16 of the fitting body 10 is defined by afirst sleeve 28 disposed within the fitting body. Sleeve 28 is generallycylindrical and, in the preferred embodiment of FIG. 1, is formed frompolyethylene or other such material. A ring 30 fabricated frompolyethylene or elastomeric material is disposed within and attached tosleeve 28 so as to define a flange extending generally radially inwardlyfrom the sleeve 28. Flange 30 defines a shoulder 32 adapted to becontacted by pipe 20 as will be described more fully hereafter.

A second sleeve 36 is secured to the inner surface of the ring 30.Sleeves 28, 36 and ring 30 thus define a socket 38 into which pipe 20 isdisposed.

In the preferred embodiment of FIG. 1, sleeve 36 is fabricated frommetal and serves as a stiffener for plastic pipe 20. The outer end 40 ofsleeve 36 is slightly rounded in order to facilitate the entry of sleeve36 into pipe 20.

In the preferred embodiment of FIG. 1 the various elements of theplastic pipe attaching means including the sleeve 28, ring 30, andsleeve 36, are retained in place by means of a groove 42 imparted to thesurface of body 12 by means of a suitable roll die in a mannerpreviously described. The grooving operation, provid-' ing for theestablishment of groove 42, upsets sufficient material of body 12 toindent sleeve 28, ring 30, and also sleeve 36. These members are thusrigidly secured together and locked against axial movement. A secondgroove 44 further restrains sleeve 28 and cooperates with shoulder toprevent axial movement of the sleeve 28.

The depth and width of groove 42 may be controlled during the rollingoperation to provide a suitable locking mechanism for the members 28, 30and 36. It has been found that even where relatively large diameterpipes are used the second sleeve 36 is rigidly locked to the ring 30 andfirmly retained within the body 12 by the groove 42. Where the ring 30is fabricated from a non-metallic material such as a polymer or anelastomer, the grip provided the second sleeve 36 by the groove 42appears to be particularly well enhanced.

As is evident from FIG. 1, socket 38 has a transverse dimension slightlyin excess of the wall thickness of pipe 20 such that pipe 20 is snuglyreceived within the socket.

Sealing and gripping means adapted to cooperate with the fitting bodyand the external surface of pipe are provided at the end of body 12.Such sealing and gripping means is defined by a tapered or generallyfrusto-conical seat 46 defined in body 12, an elastomeric gasket 48, anda compression nut 50.

Gasket 48 is defined by a tapered external surface 54 adapted tocooperate with seat 46, and an internal cylindrical wall 56 adapted tosealingly engage the external surface of pipe 20.

Compression nut is provided with threads 58 adapted to engagecomplementary threads 60 provided on body 12. As compression nut 50 isadvanced onto body 12, gasket 48 will be caused to become compressed orwedged within the space defined by the seat 46 and the internal walls ofcompression nut 50 with the result that surface 54 will sealingly abutseat 46 and wall 56 will provide sealing engagement with the externalsurface of pipe 20.

Gasket 48 and compression nut 50 cooperate to provide both sealing andgripping of the pipe 20. The sealing function of gasket 48 serves toretain any fluid that may leak past the sleeve 28 or past the inner endof pipe 20 thus to retain such fluid within the confines of the fittingbody 12. The gripping action of the gasket 48 serves to increase thepull resistance of pipe 20 thus making it difficult to separate pipe 20from the fitting body by application of an axial force to pipe 20.

In order to enhance the sealing of the fitting a resin or other adhesivemay be applied at the interface of the external surface of pipe 20 withthe internal surface of sleeve 28. Sleeve 28, in the preferredembodiment of FIG. 1, extends over the inner end of pipe 20 a distancesufficient to insure the establishment of an adequate adhesion surface.Through the application of a resin or other adhesive to the end of pipe20 before assembly of the fittings, a fluid tight connection isestablished between the pipe 20 and the liner 28 as the fitting is madeup. Similarly a small amount of adhesive may be applied to the end ofpipe 20 in order to provide sealing at the shoulder 32 after pipe 20engages the shoulder.

Turning now to the external surface of the liner 28, adhesive may beapplied to such surface in order to enhance sealing between liner 28 andthe internal wall of body 12. Similarly, adhesive may be used on theexternal surface of the sleeve 36 and on the external surfaces of ring30.

Turning now to FIG. 2 there is shown an alternate embodiment of theinvention in which the plastic pipe attaching means is provided ateither end of the fitting body in order to define a union coupling forthe purpose of securing plastic pipe to plastic pipe. Thus, in FIG. 2there is shown a fitting body 62 having identical ends defined by athread surface 64 and a tapered seat 66. A first sleeve 68 is disposedwithin body 62 and a ring 70 is disposed within sleeve 68. A secondsleeve 72 is attached to ring 70. Sleeve 72 together with sleeve 68 andring 70 define a pair of sockets 74, 76 for the purpose of receivingpipes 78.

A pair of compression nuts 80 are provided. at either end of body 62 andtogether with gaskets 82 provide sealing and gripping means for each ofthe pipes 78 in a manner similar to that described with reference toFIG. 1. It should be understood that in all respects the attaching meansfor the respective pipes 78 of FIG. 2 is similar to that described withreference to the attaching means for the pipe 20 of FIG. 1.

are defined to restrain axial movement of sleeve 68.

MODIFICATIONS OF THE INVENTION Several modifications of the preferredembodiment should be considered within the spirit of the invention.

The invention is broadly directed to attaching means for securingplastic or other pipe to a fitting body. The body itself, in alternateembodiments, could be fabricated as a part of a valve or otherinstrument to which it is desired to attach a pipe. Alternately, thebody could take forms not shown in the drawings, including such forms asan elbow, tee, male connector, cross, or other fitting form well knownto those skilled in the art.

In FIG. 1 the particular attaching means for securing the pipe 18 to thefitting body is shown as interengaging pipe threads. In alternateembodiments pipe 18 could be secured to body 12 utilizing other couplingstructures well known to those skilled in the art 'such as welding,brazing, ferrule type fittings, etc.

Ring 30 of FIG. 1 is defined by a generally annular non-metallicelement. In alternate embodiments ring 30 could be defined as anintegral part of sleeve 28. Thus, shoulder 32 could be defined by aninwardly directed flange extending from sleeve 28.

Since the basic function of ring 30 is to provide support for sleeve 36,other support means for such sleeve should be considered within thespirit of the invention.

While groove 42 functions to secure the several sleeves and the ringtogether, other attaching means such as adhesives and pins should beconsidered within the spirit of the invention.

The use of adhesives at the pipe 20 and the sleeves 28, 36, whiledesirable, should not be considered limiting. Depending on tolerancesand pressure conditions, adhesives may be eliminated.

The particular sealing and gripping means 48, 50 of the preferredembodiment is illustrative of the preferred embodiment. Other sealingand gripping means for the pipe 20 should be considered within the scopeof the invention.

What is claimed is:

1. A fitting comprising:

a generally cylindrical hollow body;

attaching means to secure a hollow pipe to said body,

said attaching means comprising;

a first sleeve received within said body and secured thereto,

a flange extending generally radially inwardly from said first sleeve,

a second sleeve formed from rigid material secured to said flange, saidsecond sleeve being spaced from said first sleeve thus defining anannular socket into which a hollow pipe may be disposed,

said socket having a substantially constant transverse dimension insection slightly in excess of the wall thickness of the pipe such thatthe pipe may be snugly received within said socket,

gripping and sealing means adapted to cooperate with said body and theexternal surface of the pipe in order to retain fluid and the pipewithin said body, said first and second sleeves extending axially fromsaid flange with said first sleeve terminating short of said sealing andgripping means and said second sleeve extending completely through saidsealing and gripping means. 2. The invention of claim 1 in which saidbody is metal and said first sleeve is non-metal.

3. The invention of claim 2 in which said second sleeve is metal.

4. The invention of claim 1 in which said gripping and sealing means isdefined as; a tapered seat in said body, an elastomeric gasket having atapered external surface adapted to cooperate with said seat and aninternal cylindrical wall adapted to cooperate with the external surfaceof the pipe, and a compression nut adapted to be threaded onto said bodyso as to wedge said gasket into said seat and the pipe.

5. The invention of claim 1 in which said flange is defined as anon-metallic ring disposed within said first sleeve and secured thereto.

6. The invention of claim 1 in which said first sleeve is secured withinsaid body by means of interlocking annular ribs defined in said body andsaid first sleeve.

7. The invention of claim 1 in which said first sleeve, said flange andsaid second sleeve are secured within said body by means of interlockingannular ribs defined in said body, said first sleeve, said flange andsaid second sleeve.

1. A fitting comprising: a generally cylindrical hollow body; attachingmeans to secure a hollow pipe to said body, said attaching meanscomprising; a first sleeve received within said body and securedthereto, a flange extending generally radially inwardly from said firstsleeve, a second sleeve formed from rigid material secured to saidflange, said second sleeve being spaced from said first sleeve thusdefining an annular socket into which a hollow pipe may be disposed,said socket having a substantially constant transverse dimension insection slightly in excess of the wall thickness of the pipe such thatthe pipe may be snugly received within said socket, gripping and sealingmeans adapted to cooperate with said body and the external surface ofthe pipe in order to retain fluid and the pipe within said body, saidfirst and second sleeves extending axially from said flange with saidfirst sleeve terminating short of said sealing and gripping means andsaid second sleeve extending completely through said sealing andgripping means.
 2. The invention of claim 1 in which said body is metaland said first sleeve is non-metal.
 3. The invention of claim 2 in whichsaid second sleeve is metal.
 4. The invention of claim 1 in which saidgripping and sealing means is defined as; a tapered seat in said body,an elastomeric gasket having a tapered external surface adapted tocooperate with said seat and an internal cylindrical wall adapted tocooperate with the external surface of the pipe, and a compression nutadapted to be threaded onto said body so as to wedge said gasket intosaid seat and the pipe.
 5. The invention of claim 1 in which said flangeis defined as a non-metallic ring disposed within said first sleeve andsecured thereto.
 6. The invention of claim 1 in which said first sleeveis secured within said body by means of interlocking annular ribsdefined in said body and said first sleeve.
 7. The invention of claim 1in which said first sleeve, said flange and said second sleeve aresecured within said body by means of interlocking annular ribs definedin said body, said first sleeve, said flange and said second sleeve.